The present invention relates to a magnetic disk drive having a magnetic head assembly mounted to a carriage arm, and more particularly to an improved method of mounting the magnetic head assembly which enables high recording density and assures high reliability.
Many magnetic disk drives accommodate a number of magnetic disks, and are provided with plural magnetic heads for reading and writing data. In known drives, one magnetic head corresponds to each surface of each magnetic disk. Each magnetic head is mounted at an end portion of a spring arm which, in turn, is attached to an end portion of a carriage arm. The carriage arm is a part of an actuator assembly. When an actuator of the actuator assembly is activated, the carriage arm moves, together with the magnetic head, along a radial direction of the magnetic disk medium.
A conventional method of fixing a magnetic head assembly to a carriage arm will now be explained with reference to FIGS. 26A-26C. In particular, FIG. 26A illustrates a cross-sectional view of the mounting portion when the magnetic head assembly is mounted to the carriage arm. A mounting hole 970a formed at the mounting portion 970 of each arm of the carriage arm 978 is provided to receive a cylindrical projected portion 989b of the magnetic head assembly 971 from both sides. Next, as shown in FIG. 26B, the carriage arm 978 is arranged between the dampers 911, 912. Each damper 911, 912 is respectively provided with a plurality of pressing plates 911a, 912a which are arranged like the teeth of a comb. Specifically, the upper surface of the pressing plate 911a and the lower surface of the pressing plate 912a are respectively tapered such that the dampers 911 and 912 mesh with one another. In this manner, each arm of the carriage arm 978 is held between the lower surface of the pressing plates 911a and the upper surface of the pressing plates 912a.
Further, as shown in FIG. 26C, the mounting portion 970 of the carriage arm 978 is held between the pressing plate 911a and pressing plate 912a. Under this condition, a caulking ball 913 is forcibly inserted using a caulking pin 914 into a caulking hole 989a formed in the head spacer 989. The caulking hole 989a is aligned with a hole 984a formed in the upper most arm of the magnetic head assembly 971. Together, these holes define a though hole (best seen in FIG. 23B). In particular, the caulking ball 913 is pressed into the caulking hole 989a via the hole 984a. Further, when the caulking ball 913 is provided into the caulking hole 989a, the cylindrical projected portion 989b expands its external diameter and is pressed against the internal surface of the mounting hole 970a of the carriage arm. In this manner, the magnetic head assembly 971 is fixed to the end portion of the carriage arm 978 to form the magnetic head arm.
However, once the magnetic head assembly is fixed to the carriage arm, it is difficult to remove the magnetic head assembly from the carriage arm to replace the magnetic head. Further, replacement of the magnetic head independent of the spring arm is virtually impossible due of the likelihood of damaging the spring arm. Accordingly, the use of a conventional caulk ball to fix the magnetic head assembly to the carriage arm results in a lowering of the fabrication yield, and decreased ease of maintenance.
In addition, the force generated by the caulk ball as it passes through the mounting hole is disadvantageous in that it tends to deform the head spacer. Moreover, as the caulk ball passes through the mounting hole, friction between the ball and head spacer generates dust which may subsequently cause a head crash.
Alternatively, instead of using a caulk ball, the magnetic head assembly may be attached to the carriage arm using screws. The use of screws makes it feasible to replace the magnetic head independent of the arm. However, the use of screws requires increased spacing between the head arms of the carriage arm to provide access for installation and removal. The recent trend towards smaller disk drives having increasingly higher recording density makes it increasingly desirable to reduce the size of the magnetic head assembly including reducing the interval between the head arms of the carriage arm. In addition, the relatively high mass of screws makes it difficult to maintain the low mass characteristics required to realize a high speed actuator. Thus, the use of screws is increasingly impractical.
Accordingly, in response to the problems discussed above, one object of the present invention is to provide a magnetic head assembly which can easily and accurately be fixed to an actuator assembly of the magnetic head assembly and which can be reduced in size.
Another object of the present invention is to provide a magnetic disk drive incorporating a magnetic head assembly which can easily and accurately be fixed to an actuator assembly of the magnetic head assembly, and to provide a method of fabricating the same.
Another object of the present invention is to provide a magnetic disk drive comprising a magnetic head arm which can precisely and easily fix a magnetic head assembly and an actuator assembly and can be reduced in size.
Another object of the present invention to provide a method of fabricating the same magnetic disk drive.
Yet another object of the present invention is to provide a magnetic head assembly including a spring arm having a magnetic head, a cylindrical portion provided on the spring arm and a thin plate member having a trapezoidal cross-section and being provided at the end portion of the cylindrical portion.